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Surface emitting laser

a laser and surface technology, applied in the direction of laser details, laser optical resonator construction, semiconductor lasers, etc., can solve the problems of poor yield, inability to obtain an active layer with uniform characteristics, and decrease the yield, and achieve excellent reliability

Active Publication Date: 2012-01-12
FURUKAWA ELECTRIC CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The present invention provides a surface emitting laser device that includes a current confinement layer formed of a compound including Al and an oxidized insulating substance. The device also includes a graded-composition layer that contacts the current confinement layer and has an aluminum composition ratio decreasing monotonically as a distance from the current confinement layer increases. The graded-composition layer is oxidized from an interface with the current confinement layer to at least a portion of the oxidation stop layer. The device has excellent reliability and can be manufactured using a simple method.

Problems solved by technology

However, when manufacturing the device, because it was difficult to control the oxidation of regions near the interfaces between oxidized regions of the current confinement layer and the AlGaAs graded-composition layers, peeling of the layers occurred near the oxidized regions, resulting in poor yield.
When the current confinement layer was near the active layer, the unevenness of the oxidation penetration at the interfaces between the oxidized regions and the non-oxidized regions made it impossible to obtain an active layer with uniform characteristics.
In addition, dislocations caused by strain occurred in the active layers, further decreasing the yield.
Even if there were no problems during manufacturing, the resulting devices had poor long-time reliability.

Method used

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first embodiment

[0059]the present invention relates to a surface emitting laser that is suitable for manufacturing by the MBE, and to a manufacturing method thereof.

[0060]With the MBE crystal growth, the AlGaAs graded-composition layer whose aluminum composition is continuously changed can be obtained by growing the crystal while gradually changing the temperature of the raw material (cell). However, flux control and reproducibility of the composition profile are still problematic, making it difficult to grow an AlGaAs graded-composition layer in which a continuously-changed aluminum composition. To cope with this problem, a digital alloy technique using a short-period superlattice is utilized. The digital alloy technique is for manufacturing compound semiconductor crystal with pseudo-different compositions by combining two types of thin compound semiconductor crystal, for example. In the first embodiment, AlGaAs and GaAs are combined to create AlGaAs with pseudo-differing compositions. By alternat...

second embodiment

[0082]the present invention relates to a surface emitting laser that is suitable for manufacturing by the MOCVD, and to a manufacturing method thereof.

[0083]The MOCVD differs from the MBE in that the composition of AlGaAs can be changed by controlling the flow rate of raw material gas, and therefore the MOCVD can be used to easily form the AlGaAs graded-composition layer in which the aluminum composition changes continuously. Accordingly, the second embodiment uses an upper graded-composition layer 111 in which the Al composition ratio decreases linearly from the current injection portion 110a of the current confinement layer 110 to the second p-type spacer layer 112 and a lower graded-composition layer 109 in which the Al composition ratio decreases linearly from the current injection portion 110a of the current confinement layer 110 to the topmost layer of the active layer 106.

[0084]The following is a detailed description of the lower graded-composition layer 109 and the upper gra...

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Abstract

A surface emitting laser includes a cavity region formed on a group-III-V compound substrate, which includes an active layer and a current confinement layer that has an aluminum oxide compound and confines a current path through which a current is injected into the active layer, an upper DBR mirror and a lower DBR mirror formed on the substrate, sandwiching the cavity region, and a graded-composition layer disposed to contact the current confinement layer, which has an aluminum composition ratio decreasing monotonically as a distance from the current confinement layer increases. The graded-composition layer includes a first region that contacts the current confinement layer and an oxidation stop layer that contacts the first region and that has a change rate of the aluminum composition ratio larger than that of the first region. The graded-composition layer is oxidized from an interface with the current confinement layer to at least a portion of the oxidation stop layer.

Description

[0001]The contents of the following Japanese patent application are incorporated herein by reference: No. 2010-155039 filed on Jul. 7, 2010.BACKGROUND[0002]1. Technical Field[0003]The present invention relates to a surface emitting laser, and more particularly, to a surface emitting laser including a current confinement layer that confines a current path through which current flows between electrodes.[0004]2. Related Art[0005]The current confinement layer includes an oxidized insulating layer obtained by selectively oxidizing compound semiconductor including aluminum, such as AlAs, and an opening portion made of the compound semiconductor including aluminum in which a high current (carrier) density is obtained by the oxidized insulating layer.[0006]To increase current input efficiency in such a semiconductor laser device, one idea is to provide, on both sides of the current confinement layer, graded-composition layers of AlGaAs in which the aluminum composition ratio gradually decre...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): H01S5/323H01S5/18
CPCH01S5/02208H01S5/02284H01S5/02288H01S2304/04H01S5/18311H01S5/18322H01S5/18369H01S5/0425H01S5/02253H01S5/02251
Inventor KAWAKITA, YASUMASASHIMIZU, HITOSHIKAGEYAMA, TAKEO
Owner FURUKAWA ELECTRIC CO LTD